Slow wave sleep disruption increases cerebrospinal fluid amyloid-β levels

Area of Science:

• Neuroscience
• Sleep Medicine
• Biomarkers of Alzheimer's Disease

Background:

• Chronic sleep disruption is implicated in Alzheimer's disease (AD) pathologies, including amyloid-beta (Aβ) plaque formation.
• Previous research suggests a link between sleep deprivation and increased Aβ, but specific sleep aspects modulating AD biomarkers remain unclear.

Purpose of the Study:

• To investigate the impact of specific sleep disruptions on key Alzheimer's disease biomarkers.
• To determine whether acute disruption of slow-wave activity or chronic poor sleep quality affects Aβ and tau levels.

Main Methods:

• Seventeen healthy adults (35-65 years) underwent actigraphy for sleep monitoring.
• Polysomnography was used to disrupt slow-wave activity, followed by cerebrospinal fluid collection.
• Cerebrospinal fluid biomarkers including Aβ40, tau, and YKL-40 were measured and compared to a sham condition.

Main Results:

• Acute disruption of slow-wave activity specifically increased amyloid-beta40 levels (r = 0.610, P = 0.009).
• This effect was independent of sleep duration or efficiency and did not affect other measured proteins.
• Poorer overnight sleep efficiency over several days was associated with higher tau levels (r = 0.543, P = 0.045).

Conclusions:

• Acute slow-wave activity disruption elevates amyloid-beta levels, suggesting a direct impact on Aβ metabolism.
• Chronic poor sleep quality, indicated by reduced sleep efficiency, is linked to increased tau.
• These findings highlight the specific roles of different sleep characteristics in modulating neuronal protein biomarkers relevant to Alzheimer's disease.